1. Field of the Invention
The present invention relates to a variable length intake control device, which varies a length of an intake passage of an engine. The present invention also relates to a straddle-type vehicle incorporating such an intake control device.
2. Description of the Related Art
Conventionally, an intake control device is known, which varies a length of an engine air intake passage of an engine to change an intake efficiency to change an output characteristic of the engine. For example, when the engine speed is low, the intake control device lengthens an intake pipe length to increase the torque output of the engine at lower engine speeds. In contrast, when the engine speed is high, the intake pipe length is shortened to increase the torque output of the engine at higher engine speeds.
Some intake control devices include a movable intake pipe that is moved between a coupled position, in which it is coupled to a stationary intake pipe coupled to an intake port of an engine, and a separated position, in which it is separated from the stationary intake pipe, by a driving force of an actuator (see, for example, Japanese Patent Publication No. 09-184423). Such intake control devices comprise a potentiometer for detection of a position of the movable intake pipe. The control device detects positional deviation of the moving intake pipe on the basis of a detected value of the potentiometer to correct a position of the moving intake pipe.